<template>
  <div class="wrapper">
    <span>{{ num }}</span>
    <button @click="add">+</button>
  </div>
</template>

<script>
export default {
  data() {
    return {
      num: 0
    };
  },
  methods: {
    add() {
      this.num++;
    }
  }
};
</script>

<style>
.wrapper {
  background: greenyellow;
}
</style>
